Adsorption of Cr(VI) from Aqueous Solution by two Kinds of Pillared Bentonites

2013 ◽  
Vol 690-693 ◽  
pp. 1037-1040
Author(s):  
Zhen Wang ◽  
Ze Sheng Cheng ◽  
Yu Liu ◽  
Na Na Bo ◽  
Shu Ping Li

The hydroxy-aluminum pillared bentonite(OH-Al-bent) and aluminum pillared bentonite(Al-bent) were synthesized and characterized by XRD and SEM analysis. The yield of products and the adsorbent capabilities for Cr(Ⅵ) from aqueous solution were investigated, and the optimal experimental conditions including adsorption time, reagent dosage, the initial concentration of Cr(Ⅵ) and PH that might influent the adsorption performance were also investigated. It was observed that the adsorption capabilities of OH-Al-bent was better than Al-bent. The efficiency of Cr(Ⅵ) removal were better when the dosage of the sorbent was higher. And a reagent dosage of 7g/L, adsorption time of 60min, PH of 4 were selected as an optimum conditions.

2012 ◽  
Vol 588-589 ◽  
pp. 47-50
Author(s):  
Ze Sheng Cheng ◽  
Zhen Wang ◽  
Yu Liu ◽  
Na Na Bo

Alkali lignin, Modification, Quaternary ammonium salt, Cr(Ⅵ), Anion adsorbent Abstract. LIA(lignin ionic adsorbent) was synthesized by modified alkali lignin after reaction with epichlorohydrin and dimethylamine or diethylamine by using the modifying agents of N-methylmorpholine (NMM) in the presence of organic medium of N,N-dimethylformamide(DMF). The LIA was characterized by FTIR spectroscopy and elements analysis, the yield of products and the adsorbent capabilities for Cr(Ⅵ) from aqueous solution were also exploited. The factors that might influent the adsorption performance were investigated, such as adsorption time, reagent dosage and the initial concentration of Cr(Ⅵ). It was found that the efficiency of Cr(Ⅵ) removal were better when the amount of the sorbent was increased. But the removal efficiency was reduced as the initial concentration of Cr(Ⅵ) increased. The contrast result of the two synthesis processes also proved the yields of sample 3 (modified alkali lignin using diethylamine) was higher than sample 2 (modified alkali lignin using dimethylamine). And the adsorption capabilities of sample 3 were also better than sample 2.


2012 ◽  
Vol 268-270 ◽  
pp. 229-232 ◽  
Author(s):  
Wei Ying Zhang ◽  
Dan Chen ◽  
Xiao Li ◽  
Xiao Guang Ying

We prepared alginate-chitosan (ALG-CTS) complexes through ionic interaction, and then obtained Cu (II)-imprinted alginate-chitosan complex microspheres (Cu-ALG-CTS) by coupling with ionic imprinting technology. To investigate the effects of experimental conditions on adsorption behavior, we performed a series of experiments including changing the initial concentration of Cu (II) ions and adsorption time. We found that the adsorption capacity increases with the initial concentration of Cu (II) ions. The Cu (II) ions adsorption reaches the maximum of 70.54mg/g after adsorbing for 13h when the initial concentration of Cu (II) ions is 60μg/ml. Cu-ALG-CTS shows much higher adsorption for Cu (II) ions than Zn (II) ions. And the adsorption kinetics and equilibrium adsorption isotherm were further studied.


2013 ◽  
Vol 750-752 ◽  
pp. 1262-1266
Author(s):  
Li Xiu Peng ◽  
Qin Ai Lin

The adsorption process of Cr (VI) in aqueous solution on activated carbon prepared by wheat straw was investigated to study the effect factors on adsorption properties. adsorption mechanism was discussed. The results showed that the adsorption performance was influenced by dosage, initial concentration and adsorption time. Adsorption reached equilibrium after 100 min at temperature 25°C. The highest removal efficiency can reach 94%. The results indicated that activated carbon as adsorbent can effectively deal with waste water containing (VI).


2013 ◽  
Vol 690-693 ◽  
pp. 1049-1052
Author(s):  
Zhen Wang ◽  
Na Na Bo ◽  
Ze Sheng Cheng ◽  
Ying Liu ◽  
Yu Liu

Lignin-based anionic exchange resin was synthesized by modified alkali lignin after reaction with epichlorohydrin and triethylamine in the weak alkaline medium provided by pyridine in the organic medium of N,N-dimethylformamide (DMF). The influence of pyridine on synthesis process and yield of products were discussed. The product was characterized by FTIR spectroscopy analysis and the adsorbent capabilities for N from aqueous solution were also exploited. The factors that might influent the adsorption performance were investigated. An adsorbent dosage of 0.2g, adsorption time of 100min, pH of 4 and the initial concentration of nitrate concentration was 10mg/l were selected as optimum conditions.


2011 ◽  
Vol 356-360 ◽  
pp. 493-497 ◽  
Author(s):  
Zong Ning Li ◽  
Zong Qiang Zhu ◽  
Mei Na Liang ◽  
Hong Dong Qin ◽  
Yi Nian Zhu

The influences of adsorption temperature, adsorption time, dosing quantity, adsorption environment pH value, initial concentration and bamboo charcoal type on adsorption of bamboo charcoal adsorb ammonia nitrogen in wastewater are studied. The result shows that the maximum adsorption values are 1.1715 mg/g and 0.9115 mg/g respectively at 25°C and 40°C. Bamboo charcoal can easily absorb ammonia nitrogen at low temperature condition. 180 min is a suitable adsorption time. Increasing bamboo charcoal dosing quantity is helpful to improve efficiencies of ammonia nitrogen removal in wastewater, but the adsorption capacity is declining as bamboo charcoal dosing quantity increasing. Solution pH value has a great impact on the adsorbed amount, the adsorbed effect in alkaline solution is much better than in acid one’s. The adsorption ability of the moderate temperature bamboo charcoal is higher than the high temperature one’s.


2013 ◽  
Vol 726-731 ◽  
pp. 2107-2110 ◽  
Author(s):  
Han Zhou ◽  
Xue Gang Luo ◽  
Xiao Yan Lin

The removal of strontium from aqueous solution with collagen fiber immobilized tannins was studied. The effects of several experimental parameters such as pH, dosage, temperature, contact time and initial concentration of strontium on removal efficiency of strontium were investigated to determine the optimum conditions of strontium sorption process. The adsorbent was characterized by SEM and FTIR analysis. The results of regression analysis indicated that temperature parameters were not individually statistically significant for Sr2+ adsorption. However, the efficiency of strontium adsorption increased with the increase in pH and dosage. The adsorption capacity was increased with increasing initial concentration of Sr2+. The removal efficiency of Sr2+ was 49% at optimum pH of 6 and initial concentration of 20mg/L. Moreover, the absorption data were fitted well to the Langmuir sorption isotherm model.


Author(s):  
Jing-song Wang ◽  
Zheng-lei Bao ◽  
Si-guang Chen ◽  
Jin-hui Yang

This study focuses on developing a new method to remove uranium from aqueous solution. Chitosan and ferrous ions were used together to remove uranium ions from aqueous solution. Through two-step pH adjustment, the uptake behavior of chitosan and ferrous ions toward uranium in aqueous solution using batch systems were studied in different experimental conditions. The experimental results indicated that the removal of uranium by synergetic effect of chitosan and ferrous ions was more effective than the way of adsorbing uranium ions by chitosan alone. Under the given experimental conditions, the concentration of the residual uranium in the effluent after chitosan and ferrous ions treatment could meet the discharge standard (< 0.05mg·l−1) when initial concentration of uranium ions was 10 mg·l−1 or 100 mg·l−1. The synergetic effect of chitosan and ferrous ions including adsorption, coacervation and coprecipitation, are responsible for the high removal rate of uranium.


2011 ◽  
Vol 356-360 ◽  
pp. 502-505 ◽  
Author(s):  
Yong Yin Zhang ◽  
Li Ping Wang ◽  
Er Deng Du ◽  
Yi Zhong Chen

A kind of 4A zeolite, which was modified by magnesium chloride and aluminum chloride, was used to treatment phosphorus wastewater. The effect of several parameters on phosphorus removal was also investigated, including zeolite dosage, pH, phosphorus concentration and the adsorption time. The results showed that, under the conditions of pH 7, the amount of modified 4A zeolite 0.05g, reaction time 15min, room temperature, the removal efficiency of phosphorus with initial concentration 2mg/L reached 98%. The SEM analysis explained that crystalline structure of 4A zeolite has changed after modification, thus resulted in the improvement of adsorption capacity. What’s more, the phosphorus removal mechanism was also discussed.


2014 ◽  
Vol 353 ◽  
pp. 33-38
Author(s):  
Rafique Ullah ◽  
Biplob Kumer Deb ◽  
Mohammad Yousuf Ali Mollah

Chromium (VI) is known to be carcinogenic to humans and thus it is important to ensure the removal of Chromium (VI) from aqueous solutions and industrial effluents. The present study introduces a good alternative method for Cr (VI) removal from aqueous solutions at ambient temperature by adsorption, allowing the development of newer, lower operational cost, and more efficient technology than other processes already in use. Adsorption was found to be dependent on pH and initial concentration of Cr (VI) solution. Results of adsorption studies suggest that pristine iron oxide and silicon (IV) oxide removes 72.10% and 24.73%, respectively. The iron oxide – silicon (IV) oxide composite, prepared in this work, removes 93.88% Cr (VI) in 20 minutes from aqueous solution at an initial concentration of 50 mgL-1at pH 4.8 ± 0.2. The effect of concentration, contact time, adsorbent dose and solution pH on the adsorption of Cr (VI) were studied in detail in batch experiments. Studies of the sorption kinetics shows that equilibrium adsorption was attained in 20 minutes depending on other experimental conditions. The kinetic data justified Lagergren’s first-order kinetic equation. Adsorption isotherm study showed that the results fulfilled the Langmuir Model of adsorption isotherm. The maximum adsorption (98.28%) was recorded at pH 3 in 90 minutes for the initial Cr (VI) concentration of 50 mg L-1. Therefore, it can be concluded that iron oxide – silicon (IV) oxide composite is a potential adsorbent for adsorption of Cr (VI) from aqueous solution.


2015 ◽  
Vol 768 ◽  
pp. 89-95 ◽  
Author(s):  
Han Qiao Liu ◽  
Xian Xu ◽  
Zhen Hua Wu ◽  
Guo Xia Wei ◽  
Lei Sun

Biochar, a production of cotton/sludge pyrolysis, was used as an adsorbent for the removal of heavy metals from aqueous solutions. In this paper, it was assessed that the effect of biochar produced parameters including pyrolysis temperature and heating rate, adsorption time, solution pH and biochar modification on removal of Cd from aqueous solution, and the removal effect of heavy metals from mixed aqueous solution was also studied. The results showed that the optimum conditions were pyrolysis temperature of 550°C, heating rate of 5°C/min, adsorption time of 90min, biochar dosage of 10g/L and solution pH=6, respectively. And the effect was a little increased when the biochar were impregnated with chemicals. About 99% Cd, Pb and Zn were removed from aqueous solution using biochar under the optimum conditions.


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